Frequently Asked Questions

Is Accord on npm?

Not yet. Run npm pack in the repository and install the tarball. See Getting Started.

Do I need Effect?

No. The core has zero runtime dependencies. Effect is an optional peer for @marcelsud/accord/effect.

Which Node.js version?

24 or newer. Accord uses node:sqlite and other Node 24 features.

Class, factory, or event-evolved aggregate?

Start with a class. Use a factory when methods need services or a shared context. Use an event-evolved aggregate when you want state to be a fold of events, declared command contracts, commandId/expectedVersion, or HTTP exposure.

Why does my view return null?

Views materialize on flush(). Read with { atLeast: receipt } to catch up first.

Why did my policy run twice?

Delivery is at-least-once. Make the action idempotent with the envelope id.

Why did I get Unexpected instead of my error?

Something threw, or you returned a rejection that isn't declared in the contract's rejects, or event data failed its schema. Check error.cause.

Can I use it in the browser or on the edge?

The core is plain ESM, but it is built and tested for Node.js 24. serve() returns a standard Request => Response handler. Other runtimes aren't documented yet.